Hi there ! 

I've been working on Diver Down lately, (especially with the Post Jam Jam) and was able to make a few changes : 
- The whole project was switched from URP to HDRP. On the one hand, it allowed me to make the lights volumetrics, on the other hand, I had to fix all the materials (that was loooong).
- Since the rest of the scene was looking too dark after those changes, I made the important objects more visible by making them glow a little. The fog is now less performance costly since it's not made of particles anymore. Sadly I had to let down the orthographic camera for a perspective one for technical reasons.
- I added a few other effects such as caustics on the ground and particle made god rays.
- There are now lights on the player and the button to make them more visible.
- The walls were transparent if you looked from one side, so I fixed it in Blender. Then I replaced the placeholder walls in all the levels which took me some time.
- I added three pipes cause I thought it would look cool. Makes me practice with Blender and Substance. Hopefully there'll be a few other models in the next build :)
- Yovador added a shader so that you could see the character and trapdoor through walls.

Little comparison : 

I've still got many ideas on what to do next to keep improving the game but you are welcome to leave a comment or whatever to help us :)

Thanks for reading !